Luminaires are designed to produce a predetermined light distribution pattern in an area to be illuminated, such as in parking lots, along roadways, or in other areas requiring broad or focused illumination of a surface. Luminaires generally include a housing or enclosure that supports a light socket, a high-intensity light source mounted in the socket, a light reflector mounted behind and/or around the light source, and other electrical hardware necessary to energize the light source. The illumination pattern created by the luminaire is generally defined by the shape of the light reflector mounted in the luminaire, as well as the position of the light source relative to the reflector. The reflector can form a partial enclosure about the source of light so that the inner surfaces of the reflector direct reflected light through an opening formed in a lower portion of the luminaire housing.
In the past, one-piece reflectors have been fabricated by molding or otherwise forming a flat piece of metal or other suitable reflective material into a desired reflector shape. The reflector can be formed by forming a sheet of reflective material between male and female dies that have cooperating three-dimensional shapes defining the reflector shape. Alternatively, the reflector may be formed by hydroforming the sheet of reflective material over a three-dimensional male form that defines the reflector shape as is well known in the art. In another method, the reflector may be spun by contouring a sheet of reflective material over a revolving male mandrel with a pressure tool to conform the sheet to the shape of the mandrel. In yet another method of fabricating reflectors, the sheet of reflective material may be formed using a press brake or other forming machine that successively bends the sheet along predetermined fold lines into a series of planar facets that approximate a desired curved surface of the reflector.
Reflectors have also been fabricated from multiple sheets of reflective material that have been individually shaped and formed and then assembled together to form a reflector shape. The individual parts of the multi-component reflector have either been joined together through fastening hardware or other suitable structures prior to mounting the assembled reflector in a luminaire housing, or the reflector components have been mounted individually within the luminaire housing to form the three-dimensional reflector shape within the housing.
More recently, as described in U.S. Pat. No. 6,464,378, reflectors have been fabricated from one sheet of reflective material, formed in a single hit die press or other means of fabrication, to form a series of integral reflective panels that are adapted to be joined together so that the reflective panels can be folded by hand into edge-abutting relationship to form folded reflector panels and define a predetermined three-dimensional reflector shape. The sheet of material is relatively thin to allow one or more of the panels to be curved by hand to define curved reflective surfaces, which can be joined to adjacent panels through perforated fold lines that include a series of elongated slots formed through the thickness of the sheet. These reflectors are efficient to make and store, and can be easily assembled into the three-dimensional shape at an assembly site or in the field.
In most outdoor lighting installations, reflectors of generally standard configurations and illumination lamps of generally standard sizes are assembled onto light poles of generally standard height, to provide a general illumination pattern. The illumination needs of a particular parking lot, roadway or other outdoor area are met by positioning a plurality of the standard outdoor light installations into a pattern sufficient to meet the illumination needs. Consequently, in some lighting installations that are used widely, a lighting design may throw light beyond the area of need, and may have uneven illumination of the ground, road or parking area. In many applications, a larger illuminating lamp may be required because of the loss of light outside the desired illumination area, or because of uneven lighting.
Thus, there is a need for a reflector that can be configured to provide more even and effective use of all the light that is emitted from an illumination bulb, to light particular outdoor areas.
There is also a need for a self-standing reflector and method of making that allows the reflector to be rapidly formed easily and consistently from at least one sheet of reflective material in relatively few manufacturing steps or forming operations.
There is also a need for a reflector that can provide improved illumination, or comparable illumination to conventional reflectors while using an illumination lamp of lower lumen output.
There is yet also a need for a reflector and method of making same that allows the reflector to be formed from at least one sheet of reflective material with substantially continuous curves on the inner reflective surfaces of the reflector and retained in a predetermined three-dimensional shape.